The death last month of a man who was shot by a sniper in The Bronx nearly 30 years ago has ruled a homicide by the Medical Examiner’s Office, police sources said yesterday.

Gilberto Medina, 70, was left paralyzed from the waist down when he was shot by a mystery gunman firing from a rooftop on Oct. 25, 1977, at the intersection of Leggett Avenue and Fox Street, the sources said.

Details about the shooting were not immediately available. Cops last night were trying to locate their records, which were in storage, a police spokeswoman said.

A source said Medina was heading to work when he was struck in the spine by the gunman’s bullet.

On March 21, Medina was discovered dead in his bed at his home, not far from where he’d been shot.

The Medical Examiner’s Office concluded he died of complications from the shooting.